MIL-W-16878 PVC Type B 105°C 600V

Type B identifies a specific MIL-W-16878 wire construction with PVC insulation, a 600V rating, and defined temperature and dimensional requirements.

The Type B designation distinguishes this construction from other MIL-W-16878 wire types that may use different insulation materials, voltage ratings, or temperature capabilities. For replacement or specification work, the full wire type should be matched rather than selecting a product based only on conductor gauge or voltage.

Full annealing makes the copper softer and easier to bend, helping improve flexibility during internal equipment wiring.

Annealing changes the physical condition of the copper so the conductor is more workable during routing and termination. That can be useful in panels, meters, and equipment where wire must pass through compact spaces or make relatively tight directional changes. The conductor is also tin plated, which adds surface protection and supports reliable termination.

A 19-strand construction generally offers greater flexibility because the conductor is made from more, smaller individual strands.

Several Type B sizes are available with either 7-strand or 19-strand conductors. For example, 22 AWG is listed in both 7/30 and 19/34 constructions. Both meet the nominal conductor size requirement, but the finer-stranded version can be easier to route in equipment where flexibility is important. The finished outside diameter may also differ slightly.

The low-temperature rating indicates that the insulation is designed to remain suitable within environments that may reach temperatures as low as -55°C.

Temperature ratings define the range within which the wire construction is intended to perform. For equipment that may be stored, transported, started, or operated in cold environments, the lower temperature limit can be just as important as the 105°C upper rating. The complete installation should still be evaluated for mechanical movement, environmental exposure, and applicable equipment requirements.

No. VW-1 indicates that the wire has passed a defined vertical flame test, but it does not mean the wire cannot burn or that it is suitable for every fire-rated application.

The UL VW-1 test evaluates flame propagation under specified test conditions. Custom Cable Corp. lists this MIL-W-16878 Type B wire as passing the VW-1 flame test. That is useful when flame performance is part of an internal equipment wiring specification, but it should not be interpreted as a universal fire-resistance rating.